To get to the National Cryptologic Museum, visitors must scan the edges of Route 32 for a small brown sign. It points down an alley that vanishes between a row of shrubs behind a gas station. There, in a drab former motel with tinted windows and rusting pillars, stands what was until recently the country's only espionage museum.

The museum has rooms full of artifacts, including tank-sized supercomputers and a full set of legendary Enigma cipher machines. But the museum has taken a perverse pride in obscurity rivaled only by its next-door neighbor, the National Security Agency, which happens to run it.

"It's been a well-kept secret for a long time," says Aramus Neill, 74, a retired NSA codebreaker who volunteers once a week as a docent.

Down the highway in downtown Washington, however, an upstart spy showplace is proving that espionage museums don't have to be as clandestine as the agencies they chronicle.

In its first month, the splashy $40 million International Spy Museum drew more visitors than the cryptologic museum did in the past two years. Its developers - the same team of entrepreneurs responsible for Cleveland's Rock and Roll Hall of Fame and Museum - are not shy about the profit motive driving it all.

Thousands of visitors a week pay $8 to $11 admission to ogle a working replica of James Bond's Aston Martin from Goldfinger. Teen-agers gather in knots around spy gizmos like the necktie camera, exploding tree stump, and "dog doo" transmitter. Even the elevator pulses with lights, and a recorded voice teases riders: "We'll be watching you."

"We think museums should be fun," says Peter Earnest, the museum's executive director. "To engage the public, you have to go beyond display cases in a dusty hall with little things at the bottom you can barely read."

So forgive the folks up at the NSA museum if they chafe at comparisons.

The longtime curator, Jack E. Ingram, says that even a former Disney whiz told him that the cryptology museum was just fine without a lot of razzle-dazzle.

"He said, 'Don't overglitz it,'" Ingram says. "Which was fine, because we didn't have any money to overglitz it."

Yet even before the International Spy Museum opened in July, the NSA museum - like the NSA itself - was coming to grips with the perception that time had passed it by.

A private fund-raising group, the National Cryptologic Museum Foundation, has been talking quietly for years about moving the museum to a bigger and newer building, somewhere in Anne Arundel County. The foundation board hopes to offer patrons more to nosh on than vending-machine candy. And it wants to strike a deal with a hotel so that groups of visitors will have a place to stay.

There is just one problem.

"We need to raise about $34 million," says John E. Morrison, a retired Air Force intelligence officer who is president of the fund-raising group. For now, most donations come from calendar sales and from coins dropped in an old artillery shell at the museum door. Suffice it to say that the project could take a few years.

Morrison, 85, was part of a group of retired national security officials who once tried to fan interest in the idea of a national museum in Washington on the history of espionage.

"It never got off the ground," recalls Earnest, the spy museum director and a retired chief of the CIA's public affairs office. "One of the reasons may be that they were all intelligence officers, not fund-raisers."

NSA officials, meanwhile, sniff that they have bigger things to do at the moment than outwit another spy museum.

"Our level of promotions," says NSA spokesman Patrick Weadon, "is appropriate for an organization whose mission is to provide and protect America's most critical communications."

The NSA museum took shape in 1990, when the Fort Meade eavesdropping agency quietly purchased the bankrupt Colony 7 Motor Inn and stocked it with Cold War artifacts. It opened to the public in December 1993.

A public museum was a jagged break for an agency that had long denied its own existence. Some saw it as a bid to curry public favor as critics in Congress were questioning the agency's usefulness after the Cold War - and before Sept. 11.

But make no mistake - the NSA did not go Madison Avenue.

"When the museum opened, we didn't tell anybody," says Ingram, the longtime curator. "The NSA wasn't doing news releases then."

It took a month before word of the ostensibly public museum leaked to the news media.

For its first few years, people who succeeded in finding it had to navigate a fence topped with razor wire to get to the front door. A sign still posted inside - it is no prop - conveys a paranoia that feels like a leftover from the Cold War: "Uncleared facility. No classified talk. Remove badges."

The museum's exhibits are thoughtful and often one-of-a-kind, attracting more than 45,000 people this year. But they are heavy on small text, glass-cabinet display cases and techno-mumbo jumbo.

One sign describes a refrigerator-sized console of knobs and meters as a "telemetry demodulation" device.

Say what?

Don't expect much help from the panel, which lists its features as "data multiplexing," "quality control plotting," and "digital tape generation."

The International Spy Museum, in contrast, was founded by broadcasting and sports marketing baron Milton Maltz.

Maltz likes to point out that he briefly worked for the NSA while a Navy reservist in the 1950s. "I was reviewing and analyzing documents, which I prefer not to discuss at any great length," he says.

But his current approach to publicity shares nothing with that of his erstwhile employer. The spy museum's opening week in July featured a pair of swank parties and a preview for the media. One ceremony saw a half-dozen acrobats in black trench coats "spy diving" off the museum's roof into a banner declaring "Mission Accomplished."

The public relations staff landed three stories in The New York Times, six in The Washington Post, and 500 on television stations from coast to coast.

The Spy City Cafe beckons with promises of "killer sandwiches." And a formal restaurant, Zola, is drawing reviews of its own accord. The sleek museum gift shop sells everything from Halloween-grade fake mustaches to night vision goggles and a $2,000 machine that sniffs out explosive residue in mail.

All this is typical of Maltz, who once proposed a museum in San Francisco with fake fog and mock earthquakes. In a ballot referendum two years ago, voters there killed the idea - some on the grounds of tackiness.

At the NSA's museum, a bigger budget could buy similar sizzle. But some question the wisdom of diverting money from the agency's core mission.

"Could any story be told more effectively with multimedia? Probably yes," says H. Keith Melton, a historian who has lent items from his private stash of spy artifacts in Florida to both museums. "But I'd rather see them out catching terrorists."

Others say that the cryptologic museum's dowdy anonymity is part of its charm.

"If you think of the genre, it's perfect," says Linda McCarthy, a former CIA agent and museum consultant who designed the CIA's employees-only museum. "Think of how many intel ops [intelligence operations] go on in low-slung, 1960s-era motels," she said. "The idea is you do not stand out."

For now, anyway, the NSA museum will continue to draw diehards such as Isaac Saltpeter, 24, an unemployed supercomputer specialist from Baltimore more interested in vintage Cray computers than in 007.

"Codebreaking isn't sexy, except to a person of a certain mentality," he said in the nearly empty museum one recent weekday. "I have to admit I'm that sort of geeky person."

National Cryptologic Museum

Founder: The National Security Agency, Fort Meade.

Location: Former 1960s-era motel, down an alley behind a gas station at Fort Meade, in Anne Arundel County.

Grand opening: Press not notified.

Admission: Free.

Budget: Undisclosed, but NSA spokesman describes as "shoestring."

Visitors in October: 3,976.

Sample artifacts: Full set of Enigma cipher machines; Bombe codebreaking machine; Cray mainframe computer; MISTE II, described in placque as "a portable miniaturized, totally integrated UHF SATCOM transceiver for secure voice and data transmission."

International Spy Museum

Founder: The Malrite Company, Cleveland.

Location: In a renovated historic building in downtown Washington, a short walk from the National Mall.

Grand opening: Two swank parties, media preview, aerial acrobats leaping from roof.

Admission: Adults $11, children $8.

Budget: Undisclosed, but $40 million was spent to build and open it.

Visitors in October: About 45,000.

Sample artifacts: Single-shot pistol disguised in a lipstick tube; exploding tree stump; model of James Bond's Aston Martin from the film Goldfinger.